The spruce budworm, Choristoneura fumiferana, Clem., is the most significant defoliating pest of boreal balsam fir (Abies balsamea (L.) Mill.) and spruce (Picea sp.) in North America. Historically, spruce budworm outbreaks have been managed via a reactive, foliage protection approach focused on keeping trees alive rather than stopping the outbreak. However, recent theoretical and technical advances have renewed interest in proactive population control to reduce outbreak spread and magnitude, i.e., the Early Intervention Strategy (EIS). In essence, EIS is an area-wide management program premised on detecting and controlling rising spruce budworm populations (hotspots) along the leading edge of an outbreak. In this article, we lay out the conceptual framework for EIS, including all of the core components needed for such a program to be viable. We outline the competing hypotheses of spruce budworm population dynamics and discuss their implications for how we manage outbreaks. We also discuss the practical needs for such a program to be successful (e.g., hotspot monitoring, population control, and cost–benefit analyses), as well as the importance of proactive communications with stakeholders.

The egg parasitoid Trichogramma spp. (Hymenoptera: Trichogrammatidae) is a widely used biocontrol agent against lepidopteran pests. Historically, Trichogramma were deployed either by plane or by using cardboard cards on which parasitized eggs are glued and manually installed at sites. Plane deployment is costly and card installation is time consuming, but the use of Trichogramma has been shown to be efficient against several pests. In 2016 and 2017, a research project investigated the potential use of unmanned aerial system for distributing Trichogramma as biocontrol agents against two major pests: an agricultural pest of maize, the European corn borer, Ostrinia nubilalis (Hübner) (Lepidoptera: Crambidae), and a forest pest, the eastern spruce budworm, Choristoneura fumiferana (Clemens) (Lepidoptera: Tortricidae). Exposure duration of parasitized eggs to field conditions (temperature, predation, etc.) in maize fields influenced the Trichogramma’s emergence rate, suggesting that timing of parasitoid releases with their emergence is essential. Although parasitism of naturally occurring eggs in maize fields could not be compared due to the low density of the European corn borer, parasitism of sentinel eggs by Trichogramma was more prominent in plots with unmanned aircraft systems (UAS)-releases compared to control plots. For spruce budworm, treatment with Trichogramma increased egg parasitism and there was no difference between the deployment by UAS and by Trichocards. We discuss these results in the context of pest biology and management. We also discuss the advantages and shortcomings of both methods and offer insights into where future work might go to further leverage the use of UAS in managing these important pests.

The sterile insect technique is a new approach for the integrated management ofDrosophila suzukiiMatsumura (Diptera: Drosophilidae), an invasive pest in North America. We evaluated, under laboratory conditions, the mating capacities and success of maleD. suzukii, irradiated at a dose of 120 Gy, with and without competition. We also explored the tendency of females to remate depending if their first mate was irradiated or not. We observed that irradiated males have the same mating capacity as control males, copulating with, respectively, 6.4 ± 1.9 females versus 6.9 ± 2.0 females in a 24-hour period. Irradiated males won the competition 37.5% of times, which is not significantly different from competiveness of control males. Female remating can be considered infrequent and not significantly influenced by male treatment: 7.4% of the females first mated with control males and 18.8% of the females first mated with irradiated males remated when given the opportunity two days and four days after the first mating. Latency before mating and mating duration were not significantly influenced by male treatment, but by presence of male competition. Overall, irradiated males thus seem to be as performant as control males, which is an important condition for a successful sterile insect technique programme.

The elm zigzag sawfly,Aproceros leucopodaTakeuchi (Hymenoptera: Argidae), was reported for the first time in North America during the summer of 2020. Characteristic zigzag defoliation was reported in the province of Québec, Canada, on the community science website, iNaturalist. Field trips conducted to the site resulted in the collection of live specimens (a few larvae and a cocoon from which an adult emerged) and onsite observation of diagnostic defoliation and empty cocoons, confirming the presence of this exotic species in Canada. Subsequent inspection of elm trees by naturalists and scientists in the south of the province led to the conclusion that the species is more widely distributed than first expected and that the invasion is not localised to a small area. Preliminary genetic data pointed to a possible European origin of the Canadian population, but conclusive assignment to source will require examination of more specimens and the collection of reference sequences from different European and Asian populations. This is a good example of the importance of community science in the detection of new invasive species.

The emerald ash borer,Agrilus planipennisFairmaire (Coleoptera: Buprestidae), is a serious pest of ash (Fraxinusspp.) (Oleaceae) in North America. Control of emerald ash borer is difficult in natural forest settings; therefore, a classical biological control programme is the most feasible management option for this invasive, nonnative insect. Here, we report the first Canadian release and establishment of parasitoidsTetrastichus planipennisiYang (Hymeoptera: Eulophinae),Oobius agriliZhang and Huang (Hymenoptera: Encyrtidae), andSpathius galinaeBelokobylskij and Strazanac (Hymenoptera: Braconidae) in natural forests in Ontario, Quebec, and New Brunswick, Canada for the control of emerald ash borer. Releases ofT. planipennisiwere made from 2013 to 2019,O. agrilifrom 2015 to 2019, andS. galinaefrom 2017 to 2019. Trees from release sites were destructively sampled to rear out adult emerald ash borers and parasitoids 1–3 years after parasitoid release. Recoveries ofT. planipennisiwere made at 81% of release sites (13 of 16) 1–2 years after release, andO. agiliwere recovered from 29% of release sites (4 of 14) 1–3 years after release.Spathius galinaewas not recovered. These data provide important information for the development and deployment of a successful biological control programme for the management of emerald ash borer in Canada.